Pool delete fails to remove smb.conf entry

[phillxnet]

An existing Samba export is only removed from DB, not smb.conf, during an associated Pool delete. This was observed on a TW installer derived instance; but is likely unrelated to the underlying OS. So we likely fail to remove out export config when deleting a pool. N.B. this failure was associated with an initial Pool delete 'busy' failure - then followed up by a seemingly successful Pool delete re-try.

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Requires confirmation without associated initial Pool delete 'busy' fail.

[phillxnet]

Creating the same smb share and then deleting this share did, however, then remove the associated smb config. So the config removal failure looks to be associated with the Pool delete not propogating to a full smb config export removal.